The ACT will get a $20 million increase in GST funding after recommendations from the Commonwealth Grants Commission were agreed to.

Federal Treasurer Wayne Swan met his state and territory counterparts in Canberra on Wednesday morning and agreed to adopt the recommendations from the Commission.

As a result, the ACT has been allocated an extra $20 million over the next financial year due to an increase in population.

ACT Treasurer Andrew Barr has welcomed the funding boost.

"That's important obviously for longer term budgeting for the Territory," he said.

"As we go into the 20113-14 budget and beyond, it is good to get this confirmation of the Territory's share of GST funding."

But Mr Barr has raised concerns that the ACT's share could be impacted in the future, if changes proposed by the bigger states ever went ahead.

He says the larger jurisdictions are pushing for GST to be distributed on a per capita basis, rather than the current model of Horizontal Fiscal Equalisation (HFE).

"The difference between what we get under HFE and what we would get under a per capita allocation over the next four years is more than $800 million - approaching 200 million dollars a year," Mr Barr said.

"The impact that would have on service provision in the Territory if that money were taken from us is significant."